Eugeneodonts

Eugeneodonts are an extinct order of cartilaginous fish that lived from the Devonian period to the Triassic period. They are characterized by their unique tooth structure, which often consists of a large, spirally arranged set of teeth on the lower jaw, known as a "dental whorl." This dental whorl was likely used for crushing and grinding prey. The upper jaw typically had numerous smaller, sharp teeth.

Fossil remains of eugeneodonts have been found in marine deposits worldwide. Their diet is believed to have consisted mainly of mollusks and other invertebrates, though some larger species may have preyed on smaller fish. The exact phylogenetic relationships of eugeneodonts are still debated, but they are generally considered to be a distinct lineage within the Chondrichthyes, the class that includes sharks, rays, and chimaeras.

Several notable eugeneodont genera have been discovered, including Helicoprion, with its distinctive spiral tooth whorl, and Edestus, which possessed long, scissor-like tooth structures. Eugeneodonts reached their peak diversity during the Carboniferous and Permian periods, but their lineage ultimately died out at the end of the Triassic, likely due to environmental changes and competition with other marine vertebrates. Their unusual dental apparatus makes them one of the most distinctive and fascinating groups of extinct fish.